Organic semiconductor devices include such types as organic solar cells, organic electroluminescence devices (organic EL devices), and organic field effect transistors. From before, a number of compounds including such as phthalocyanine, pentacene, and oligothiophene have been developed as organic compounds that serve as p-type semiconductors to transport holes in an organic semiconductor device.
However, n-type semiconductors to transport electrons are limited to fullerene, perylene tetracarboxylic acid diimide, perfluoropentacene, etc., and research and development thereof are delayed in comparison to the p-type. An essential reason for this is considered to be instability of an organic molecular anion (a radical anion species, to be accurate) produced by a closed-shell organic molecule receiving a single electron.
Also, although not in the field of organic semiconductor devices, there is known an arrangement related to a secondary battery in which an organic compound having a phenalenyl skeleton or a derivative thereof is used as an active substance included in a positive electrode (see Patent Document 1 below). In the Patent Document 1, a trioxotriangulene (TOT) derivative is cited as an example of the organic compound having the phenalenyl skeleton (see Formula (a-3) in Chemical Formula (4) cited in Patent Document 1). However, there is no suggestion in Patent Document 1 of rendering the organic compound function as an organic semiconductor device by using it in a semiconductor layer of an organic semiconductor device.